[alsa-devel] [PATCH] ALSA: add support for disabling period irq

pl bossart bossart.nospam at gmail.com
Mon Nov 8 21:52:38 CET 2010

>>>>>> I feel that some bottom-line check is needed if we keep the linear
>>>>>> position over the buffer size even without the period irq.
>>>>>> If the app doesn't care, OK fine, the driver shouldn't care, too.
>>>>>> But then it doesn't make sense to keep the linear position, either.
>>>>> But if we can keep the linear position using the light-weight jiffies
>>>>> check, it's probably OK to keep it rather than changing the hw_ptr
>>>>> behaviour.
>>>> Well, but the point of the patch is to avoid wakeups as much as
>>>> possible.  The jiffies-check adds an unconditional wakeup for each
>>>> buffer size, thus it's against the purpose of the patch.
>>> I don't see any wakeup.
>> The CPU is woken up.  This is to be avoided.
> Nope. No timers are used. The jiffies check and hw_ptr correction should be
> done from the avail_update call invoked from an application.

ok, so I re-implemented all the points found in the reviews except for
this thread. There's already some code to see if we go beyond the
buffer boundaries, so I am not sure what the 'linear position' means.
Do I need to implement anything specific to check the validity of the
hw_ptr values? I am not clear if I need to do anything beyond the fix
attached, and I don't honestly understand all these checks with
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